The present invention is an improvement on the filter seal arrangement disclosed in U.S. Pat. No. 3,771,664, assigned to the assignee of the present invention. Such patent is directed to a filter system of the kind in which a filter liner or bag is supported by a perforate basket, in turn housed within a tank and dividing same into unfiltered and filtered liquid zones. The patented system advantageously employs a single, substantially U-cross section resilient seal ring both to seal against liquid leakage between the unfiltered and filtered liquid zones, and to seal against liquid leakage between the tank and cover. To this end an annulus is fixed coaxially atop the open end of the tank below the cover and, in cross section, is provided with two steps, the inner of which supports the open upper end of the basket by means of a flange on said basket and outer of which supports the single U-cross section resilient seal which receives therein the upper edge of the bag and is compressed against the outer step by closure of the cover. This arrangement serves, in addition to the two sealing functions above-mentioned, also to center the basket and bag within the filter tank.
The above-described, patented system has been found quite satisfactory, both operationally and from a commercial acceptance standpoint.
However, the above-described, patented system provides that communication between the interior of the filter liner and the exterior of the tank (i.e., normally communication between the unfiltered liquid zone and a source of liquid to be filtered) be through an inlet conduit fixed to and communicating through the removable cover. In many installations this causes no particular problem, particularly where the need gain access to the interior of the filter tank is infrequent and/or where the inlet piping is such as not to materially hamper removal of the cover.
On the other hand, in some types of installations, the connection of the inlet piping through the cover is a disadvantage, for example under severe filtering conditions where the cover must be opened often to change the filter liner or otherwise service the unit, and where the inlet piping is inaccessible and/or devoid of rapidly disconnectible couplings or the like, or, on the other hand, is not provided with a swivelable or flexible portion which would permit opening of the cover without disconnection of the inlet piping. The present invention is thus directed to, and solves, this problem.
Accordingly, the objects of this invention include provision of:
(1) A filter construction of the bag supporting basket type for liquid/solids filtration in which the tank cover is free of pipe connections for liquid transfer into or out of the tank and is freely removably from and installable on the open end of the tank without disconnection or manipulation of pipe connections to the tank, and without need for access to pipe connections to the tank or special quick disconnect, swivel or flexible sections in said piping.
(2) A filter construction, as aforesaid, capable of use with the same resilient seals, baskets and bags as in the filter structure disclosed in aforementioned U.S. Pat. No. 3,771,664, so as to minimize the size of inventories of parts required for manufacturing and maintenance where filter construction of both types are to be manufactured or used.
(3) A filter construction, as aforesaid, which retains the desirable cover to tank sealing, bag and liner centering, and unfiltered to filtered liquid zone sealing characteristics of the structure disclosed in above-mentioned U.S. Pat. No. 3,771,664 in spite of freeing the tank cover from pipe connections.
Other objects and purposes of this invention will be apparent to persons acquainted with apparatus of this general type upon reading the following specification and inspecting the accompanying drawings.